Is Melatonin safe?
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Is Melatonin Safe? A Comprehensive Review
Introduction to Melatonin Safety
Melatonin, a hormone primarily known for regulating sleep-wake cycles, is widely used as a supplement to address various sleep disorders. Its safety profile, especially concerning higher doses and long-term use, has been a subject of extensive research. This article synthesizes findings from multiple studies to provide a clear understanding of melatonin's safety.
Short-Term Safety of Melatonin
General Safety in Adults
Several studies have confirmed that melatonin is generally safe for short-term use in adults. A meta-analysis of randomized controlled trials (RCTs) involving 651 participants found no significant adverse effects with short-term melatonin use (up to three months). Another review corroborated these findings, indicating that melatonin is well-tolerated with minimal adverse effects such as dizziness, headache, and drowsiness.
Safety in Children and Adolescents
Melatonin has also been studied in pediatric populations, particularly for treating sleep onset insomnia. A meta-analysis of RCTs involving children and adolescents reported that melatonin is effective and tolerable for short-term use, with no significant differences in dropout rates due to adverse events compared to placebo. However, the long-term safety in this demographic remains less certain, necessitating further research.
Long-Term Safety and Higher Doses
Higher Doses in Adults
The safety of higher doses of melatonin (≥10 mg) has been less documented. A systematic review and meta-analysis involving 3861 participants found that while higher doses did not significantly increase serious adverse events (SAEs) or withdrawals due to adverse events (AEs), they did increase the risk of minor AEs such as drowsiness, headache, and dizziness. This suggests that while higher doses are generally safe, they may lead to more frequent minor side effects.
Long-Term Use Concerns
Long-term safety data for melatonin, especially beyond three months, is limited. A systematic review highlighted the scarcity of long-term RCTs, noting that most studies were of short duration (four weeks or less). The review found that while melatonin is generally safe, the lack of long-term data limits definitive conclusions about its safety over extended periods.
Special Populations and Potential Risks
Children with Autism Spectrum Disorder (ASD)
Melatonin is increasingly used to treat insomnia in children with ASD. A review of studies on prolonged-release melatonin (Ped-PRM) found it to be safe for short-term use, with common side effects including fatigue and somnolence. However, the review emphasized the need for more long-term safety data.
Patients with Intellectual Disabilities
Melatonin is also used to treat sleep disorders in individuals with intellectual disabilities (ID). While it appears effective in reducing sleep onset latency, its long-term safety in this population is not well-established. Concerns include potential drug interactions and effects on puberty, particularly in children and adolescents.
Conclusion
Overall, melatonin is considered safe for short-term use in both adults and children, with minimal adverse effects. Higher doses may increase the risk of minor side effects but do not appear to cause serious adverse events. However, the long-term safety of melatonin, especially in specific populations such as children with ASD and individuals with ID, requires further investigation. Future studies should focus on long-term use and potential risks in these vulnerable groups to provide more comprehensive safety guidelines.
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